1. Field of the Invention
The present invention relates to an inductor, and more particularly, to a spiral inductor having a micro size and high efficiency, a method of manufacturing the inductor, and a device package structure using the inductor as a packaging element.
2. Description of the Related Art
An inductor is one of the most important components forming an electric circuit, along with a resistor, a condenser, an electron tube, a transistor, and a power source, and has a coil structure in which copper or aluminum is wound in the shape of a screw several times. The inductor can suppress a sudden change of a current by inducing voltage in proportion to the amount of a current change. In this case, inductance is a ratio of counter-electromotive force generated due to electromagnetic induction according to a change of current flowing into a circuit, or a ratio of an electromotive force generated in the coil to the amount of current flowing over time into a coil. The sign of the inductor is displayed as “L” according to the first letter of linkage designating magnetic coupling.
In the case that one side of an inductor is suddenly disconnected while a current flows through the inductor, the current immediately becomes 0 and a very high voltage is generated, thereby generating a spark in the disconnected portion of a circuit. By using this theory, an inductor is used as a filter controlling a sudden change of a current and filters electric noise in various electronic appliances, oscillation circuits, and current storage devices of a power circuit.
Generally, an inductor is also used in an integrated chip (IC) or MMIC for communication. In particular, as system-on-chip (SOC) technology has advanced, a packaging technology for unification of several devices is currently being developed. Therefore, an inductor having a micro structure and excellent properties, whose manufacturing cost is low, is required.
FIG. 1 is a photograph illustrating an inductor used in a conventional IC device. Referring to FIG. 1, a conventional inductor has a structure floating on a substrate and has a coil structure in approximately the shape of a square. In order to embody the coil structure on a flat surface, a part of the coil structure is vertically separated from and passes under other parts of the coil structure floating over the substrate.
In addition, inductors in various structures may be provided on a chip. However, in view of conventional inductors requiring a considerable amount of space for installation and difficulty in manufacturing conventional inductors due to their complex coil structure, conventional inductors have a low quality factor. Particularly, in the case that many devices have to be embodied on one wafer, a process of manufacturing other devices together may be difficult due to an inductor and there is also a difficulty of embodying a packaging of a device. Also, as shown in FIG. 1, since the coil structure of the inductor has a separated space, an extremely difficult process is required, and there is a problem of generating adhesion for performing wet etching for floating the structure. In addition, a failure of the floated structure caused by external impact easily occurs and stiffness is low.